The present invention relates to an aminoalkanesulfonic acid derivative and a pharmaceutical composition for use in preventing or treating heart diseases.
Myocardial cells maintain the homeostasis of calcium through the cell membrane. When the functional disorders of the cell membrane are induced or excessive calcium ions (Ca.sup.2 +) are overloaded in myocardial cells by the drug effects etc., the myocardial cells are obstructed and that causes cardiomyopathy or myocardial necrosis.
When isolated hearts are re-perfused with Ca.sup.2+ containing medium after a short period of Ca.sup.2+ -free perfusion, contraction of myofibrils, loss of electrical activity, rupture of myocardial cells, flux of intracellular enzymes and the like are observed. This phenomenon was termed the "calcium paradox" , and it has been suggested that the Ca.sup.2+ -overload played an important part in the occurrence of this phenomenon. Namely, it was proposed that the Ca.sup.2+ -overload causes cardiomyopathy at blood re-circulation after ischemia accompanied with ischemic heart diseases and heart operations. Finally the calcium paradox causes irreversible changes of myocardial cells. It was reported that this dysfunction resulting from the calcium paradox was reduced by drugs such as calcium antagonist.
The inventors have found that the aminoalkanesulfonic acid derivative of the present invention has an excellent protective effect against cardiomyopathy resulting from the Ca.sup.2+ -overload and improving effect on hypofunction of hearts in the low Ca.sup.2+ concentration.
An object of the present invention is to provide a pharmacological composition for use in treating or preventing heart diseases, which comprises as an active ingredient an effective amount of at least one aminoalkanesulfonic acid derivative or pharmaceutically acceptable salt thereof. Another object of the invention is to provide the use of the aminoalkanesulfonic acid derivative and pharmaceutically acceptable salt thereof, for the manufacture of pharmaceutical composition for use in preventing or treating heart diseases in a mammal. Further object of the invention is to provide novel aminoalkanesulfonic acid derivatives or pharmaceutically acceptable salts thereof, which are useful as preventive medicine or remedy for various heart diseases.